As conventional technologies regarding large-size synthetic resin bottle containers with a grip, there are those described in patent documents D1 and D2. The document D1 describes a grip bottle 1 having an integrally formed grip. This bottle comprises two recessed grip portions 8, which are disposed on both sides of a body, and in which the user is able to put the thumb and fingers of a hand, and the grip 9 disposed between these two recessed grip portions 8.
This grip bottle 1 has a configuration that affords the user to carry the bottle by putting the thumb in one recessed portion 8 formed in a body 3 and the fingers in the other recessed grip portion 8 and pinching the two recessed grip portions 8.
According to the invention described in the document D1, a most recessed wall 82 of each recessed grip portion 8 is designed to have a shape in which the most recessed wall 82 would widen toward outside in a lower portion thereof. Because of this shape, the recessed grip portions 8 can be blow molded without utilizing any movable inserts.
The patent document D2 describes an invention on a handy bottle 1 with an integrally molded grip comprising two recessed grip portions 6, which are disposed on both sides of a body 3, and in which the user is able to put the thumb and fingers of a hand, and a rear wall portion disposed between these two recessed grip portions 6.
This handy bottle 1 has a configuration that affords the user to carry the bottle by putting the thumb in one recessed portion 6 formed in a body 3 and the fingers in the other recessed portion 6 and pinching the two recessed grip portions 6.
The invention described in the document D2 discloses a technology for molding recessed grip portions 6, which comprises utilizing movable inserts 22 having flat and smooth mold surfaces when the handy bottle 1 is molded in a blow mold 21. The movable inserts 22 are previously kept on standby inside the blow mold 21 at positions ranging from a central axis of a preform 20 to 2.0 to 2.6 times as much as the diameter of the preform 20. These movable inserts 22 are moved to most recessed walls 7 inside the recessed grip portions 6 at a certain time point during the blow molding operation. This movement of the movable inserts 22 is said to overcome a tendency of the recessed grip portions 6 in which the most recessed walls 7 of these recessed grip portions 6 get thick but both side walls thereof get thin.